constructing a 8x1 mux using 74153 IC and an inverter

view story

http://forum.allaboutcircuits.com – "Design of 8-to-1 MUX with enable, using the 74153 dual 4-to-1 multiplexers with enable (dual means that two 4-to-1 multiplexers in one IC package) and an inverter. Write Verilog code for the 8x1 multiplexer, which uses the Verilog code for 4-to-1 multiplexer with enable.*" My lab task is this, however I am stuck. I can design the 8x1 mux with a dual 4x1 mux and a 2x1 mux but I have no idea how am I supposed to do it with an inverter. Please help me thanks. (Embedded)